How Can Police Prove Drunk Driving?

What is a drunk driving case or DUI?

In Pennsylvania, it is illegal for drivers 21 years of age or above to drive with a blood alcohol concentration of 0.08% or higher.  It is also illegal to drive under the influence of certain controlled substances, including marijuana, heroin, cocaine, methamphetamine, as well as many mental health medications like xanex and Zoloft, and Paxil. 

Drivers can also be charged with a DUI offense even if the alcohol concentration is below 0.08%, and even if no blood was obtained by police at all.  Certain other rules relate to minors driving and have lower limits for alcohol.

What do police have to prove for a DUI in Pa?

They have to prove that you were operating and otherwise in control of a motor vehicle on a public roadway, in a particular jurisdiction (county) in Pennsylvania, and that you were under the influence of alcohol or other intoxicating substance.   Proof comes in many forms—blood, DNA, fingerprints, video recordings, police reports of their observations, interviews with suspects and others, and admissions from an accused defendant.  

There is no particular requirement in Pa or any other state that police must have scientific evidence in order to prove a DUI.  In other words, it is sufficient to convict someone of a DUI offense based merely on the opinions of the police and their own observations of the defendant.  It is up to a judge or jury to decide if that evidence is sufficient as evidence to prove guilty beyond a reasonable doubt.

What kinds of observations are police making to support a DUI?

There are numerous ones.  Some of them are ones everyone knows like the person is stumbling, fumbling their words or incoherent, smelling strongly of alcohol or marijuana, dilated pupils, red, bloodshot eyes, inability to focus, driving too slow or too fast, swerving, etc  However, police are trained to look for many other signs.  An accident, especially one that occurs at night, immediately raises suspicions of police, but they will still need to make other observations or do other investigating before they can charge a DUI. 

When police have temporarily detained you on the side of the road, they will normally talk with you, ask you questions, and try to interact with you in order to gauge whether you may possibly be under the influence, in order to further detain you and scrutinize more carefully for signs of intoxication. 

Field sobriety tests and chemical breath tests can help them to determine whether an arrest for suspected DUI is appropriate.  Police may also talk with witnesses if there are any to determine if you are under the influence.

Attorney Kathryn Roberts is ready to assist you in your DUI.  If you feel stuck and don’t know where to start in a potential DUI case, call her right away and figure out the next steps.